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![Eugeniy Paltsev](/assets/img/avatar_default.png)
Add single-register MMIO GPIO driver for complex cases where only several fields in register belong to GPIO lines and each GPIO line owns a field with different length and on/off value. Such CREG GPIOs are used in Synopsys AXS10x and HSDK boards. Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
191 lines
4.3 KiB
C
191 lines
4.3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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//
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// Synopsys CREG (Control REGisters) GPIO driver
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//
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// Copyright (C) 2018 Synopsys
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// Author: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
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#include <linux/gpio/driver.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#define MAX_GPIO 32
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struct creg_layout {
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u8 ngpio;
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u8 shift[MAX_GPIO];
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u8 on[MAX_GPIO];
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u8 off[MAX_GPIO];
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u8 bit_per_gpio[MAX_GPIO];
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};
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struct creg_gpio {
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struct gpio_chip gc;
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void __iomem *regs;
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spinlock_t lock;
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const struct creg_layout *layout;
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};
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static void creg_gpio_set(struct gpio_chip *gc, unsigned int offset, int val)
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{
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struct creg_gpio *hcg = gpiochip_get_data(gc);
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const struct creg_layout *layout = hcg->layout;
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u32 reg, reg_shift, value;
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unsigned long flags;
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int i;
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value = val ? hcg->layout->on[offset] : hcg->layout->off[offset];
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reg_shift = layout->shift[offset];
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for (i = 0; i < offset; i++)
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reg_shift += layout->bit_per_gpio[i] + layout->shift[i];
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spin_lock_irqsave(&hcg->lock, flags);
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reg = readl(hcg->regs);
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reg &= ~(GENMASK(layout->bit_per_gpio[i] - 1, 0) << reg_shift);
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reg |= (value << reg_shift);
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writel(reg, hcg->regs);
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spin_unlock_irqrestore(&hcg->lock, flags);
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}
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static int creg_gpio_dir_out(struct gpio_chip *gc, unsigned int offset, int val)
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{
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creg_gpio_set(gc, offset, val);
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return 0;
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}
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static int creg_gpio_validate_pg(struct device *dev, struct creg_gpio *hcg,
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int i)
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{
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const struct creg_layout *layout = hcg->layout;
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if (layout->bit_per_gpio[i] < 1 || layout->bit_per_gpio[i] > 8)
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return -EINVAL;
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/* Check that on valiue fits it's placeholder */
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if (GENMASK(31, layout->bit_per_gpio[i]) & layout->on[i])
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return -EINVAL;
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/* Check that off valiue fits it's placeholder */
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if (GENMASK(31, layout->bit_per_gpio[i]) & layout->off[i])
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return -EINVAL;
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if (layout->on[i] == layout->off[i])
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return -EINVAL;
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return 0;
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}
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static int creg_gpio_validate(struct device *dev, struct creg_gpio *hcg,
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u32 ngpios)
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{
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u32 reg_len = 0;
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int i;
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if (hcg->layout->ngpio < 1 || hcg->layout->ngpio > MAX_GPIO)
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return -EINVAL;
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if (ngpios < 1 || ngpios > hcg->layout->ngpio) {
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dev_err(dev, "ngpios must be in [1:%u]\n", hcg->layout->ngpio);
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return -EINVAL;
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}
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for (i = 0; i < hcg->layout->ngpio; i++) {
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if (creg_gpio_validate_pg(dev, hcg, i))
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return -EINVAL;
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reg_len += hcg->layout->shift[i] + hcg->layout->bit_per_gpio[i];
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}
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/* Check that we fit in 32 bit register */
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if (reg_len > 32)
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return -EINVAL;
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return 0;
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}
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static const struct creg_layout hsdk_cs_ctl = {
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.ngpio = 10,
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.shift = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
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.off = { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 },
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.on = { 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 },
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.bit_per_gpio = { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }
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};
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static const struct creg_layout axs10x_flsh_cs_ctl = {
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.ngpio = 1,
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.shift = { 0 },
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.off = { 1 },
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.on = { 3 },
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.bit_per_gpio = { 2 }
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};
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static const struct of_device_id creg_gpio_ids[] = {
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{
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.compatible = "snps,creg-gpio-axs10x",
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.data = &axs10x_flsh_cs_ctl
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}, {
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.compatible = "snps,creg-gpio-hsdk",
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.data = &hsdk_cs_ctl
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}, { /* sentinel */ }
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};
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static int creg_gpio_probe(struct platform_device *pdev)
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{
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const struct of_device_id *match;
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struct device *dev = &pdev->dev;
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struct creg_gpio *hcg;
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struct resource *mem;
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u32 ngpios;
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int ret;
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hcg = devm_kzalloc(dev, sizeof(struct creg_gpio), GFP_KERNEL);
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if (!hcg)
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return -ENOMEM;
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mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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hcg->regs = devm_ioremap_resource(dev, mem);
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if (IS_ERR(hcg->regs))
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return PTR_ERR(hcg->regs);
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match = of_match_node(creg_gpio_ids, pdev->dev.of_node);
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hcg->layout = match->data;
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if (!hcg->layout)
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return -EINVAL;
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ret = of_property_read_u32(dev->of_node, "ngpios", &ngpios);
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if (ret)
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return ret;
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ret = creg_gpio_validate(dev, hcg, ngpios);
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if (ret)
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return ret;
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spin_lock_init(&hcg->lock);
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hcg->gc.label = dev_name(dev);
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hcg->gc.base = -1;
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hcg->gc.ngpio = ngpios;
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hcg->gc.set = creg_gpio_set;
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hcg->gc.direction_output = creg_gpio_dir_out;
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hcg->gc.of_node = dev->of_node;
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ret = devm_gpiochip_add_data(dev, &hcg->gc, hcg);
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if (ret)
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return ret;
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dev_info(dev, "GPIO controller with %d gpios probed\n", ngpios);
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return 0;
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}
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static struct platform_driver creg_gpio_snps_driver = {
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.driver = {
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.name = "snps-creg-gpio",
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.of_match_table = creg_gpio_ids,
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},
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.probe = creg_gpio_probe,
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};
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builtin_platform_driver(creg_gpio_snps_driver);
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